62 Dr. H. Woodward — A New Gault Crustacean. 



mostly collected by herself. Miss Birley was fortunate in obtaining 

 from Mr. J. GriflSths, the resident geological collector, a small but 

 well - preserved carapace of a Gault Crustacean, believed at the 

 moment to be the usual Necrocarcinus Bechei (Deslongsch., sp.), 

 a form about as abundant in that locality as the Palceocorystes 

 Stolcesii (Mantell, sp.). The specimen, enlarged twice natural size, 

 is clearly depicted in the accompanying illustration in the text. 



Mesodromilites Birleyi, gen. et sp. nov. 



Gault : Folkestone, a, dorsal aspect ; b, profile of same specimen. Drawn twice 

 the natural size. The original specimen is in the possession of Miss Caroline Birley. 



A more careful examination of the original convinced me that 

 I was in error in referring this Crustacean to N. Bechei, or indeed 

 to any species of Necrocarcinus ; and after a lengthened search for 

 an analogue I was compelled to believe it to be a new form, 

 a thing well - nigh incredible in a formation like the Gault of 

 Folkestone, which has been 'the happy hunting-ground' for so 

 many generations of London and provincial geologists, and a spot 

 dear to the name of J. Griffiths, who for the past fifty years or more 

 has been the sole collector and geological guide of Folkestone Cliffs. 



The figures give both the dorsal and lateral aspect of the 

 carapace, and show it to be one-fourth longer than broad, very 

 tumid in the centre, having three pairs of rounded sub-central 

 tubercles (three on either side of a median dorsal line), with 

 a central tubercle placed on the posterior metacardiac region. Two 

 rather curved and elongated tubercles occur on the surface of the 

 test outside the hindmost pair of sub-central tubercles and midway 

 between them and the lateral margins of the carapace, just over the 

 posterior branchial region. Five somewhat prominent tubercles 



